New research programs were established in natural products chemistry, cellular pharmacology, ultrastructure, immunochemistry, tissue culture, and tumor cell biology. A sulforhodamine B (SRB) assay was developed for quantitating drug effects upon stratum attached cells, as was an MTT tetrazolium assay for single cell suspensions. A bicarbonate-free growth medium was developed. Evaluation of its ability to support the growh of cell lines in the screening panels is in progress. Nearly 200 human cell tumor lines have been evaluated as candidates for possible inclusion in the anti-AIDS and anti cancer drug screens. Those which grew adequately in culture, were of early passage, and were obtained from tumors wth documented pathology from patients not receiving prior chemo- or radiation therapy, are undergoing extended evaluation. The histopathology, immunochemistry, ultrastructure, growth physiology, biochemistry, and chemotype of these lines are being analyzed in detail. A procedure for Stage I in vitro anticancer drug screening was developed. Its experimental optimization and large-scale feasibility testing are nearing completion. Pattern recognition algorithms have been developed for identifying drugs which act selectively against specific subsets of cell lines. A tentative protocol for Stage II in vitro anticancer screening has been developed, and is currently being optimized in a basic research mode on a subset of cell lines with a group of standard clinical drugs. A variety of tumor lines encapsulated within polymeric microspheres have been successively tested as an in vivo assay of drug sensitivity. A novel method was developed for propogating human lung tumor lines as orthotopic xenografts in the lungs of nude mice using intrabronrhial and intrathoracic implantations. A number of cyanobacterial, tropical plant, and marine natural products with anti-AIDS activity were successfully fractionated. The chemical structures of one class of active agents has been elucidated, and several others are in the advanced stages of structure identification.